/*
 * ****************************************************************************
 * Copyright (c) 2013, Daniel Murphy All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright notice, this list of conditions
 *   and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice, this list of
 *   conditions and the following disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * ****************************************************************************
 */
/*
 * JBox2D - A Java Port of Erin Catto's Box2D
 *
 * JBox2D homepage: http://jbox2d.sourceforge.net/
 * Box2D homepage: http://www.box2d.org
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 * claim that you wrote the original software. If you use this software
 * in a product, an acknowledgment in the product documentation would be
 * appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 * misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */
package org.jbox2d.dynamics.joints

import org.jbox2d.common.Vec2
import org.jbox2d.dynamics.Body

// Updated to rev 56->130->142 of b2DistanceJoint.cpp/.h
/**
 * Distance joint definition. This requires defining an anchor point on both bodies and the non-zero
 * length of the distance joint. The definition uses local anchor points so that the initial
 * configuration can violate the constraint slightly. This helps when saving and loading a game.
 *
 * @warning Do not use a zero or short length.
 */
class DistanceJointDef : JointDef() {
  /** The local anchor point relative to body1's origin. */
  val localAnchorA: Vec2

  /** The local anchor point relative to body2's origin. */
  val localAnchorB: Vec2

  /** The equilibrium length between the anchor points. */
  var length: Float

  /** The mass-spring-damper frequency in Hertz. */
  var frequencyHz: Float

  /** The damping ratio. 0 = no damping, 1 = critical damping. */
  var dampingRatio: Float

  init {
    type = JointType.DISTANCE
    localAnchorA = Vec2(0.0f, 0.0f)
    localAnchorB = Vec2(0.0f, 0.0f)
    length = 1.0f
    frequencyHz = 0.0f
    dampingRatio = 0.0f
  }

  /**
   * Initialize the bodies, anchors, and length using the world anchors.
   *
   * @param b1 First body
   * @param b2 Second body
   * @param anchor1 World anchor on first body
   * @param anchor2 World anchor on second body
   */
  fun initialize(b1: Body, b2: Body, anchor1: Vec2, anchor2: Vec2) {
    bodyA = b1
    bodyB = b2
    localAnchorA.set(bodyA!!.getLocalPoint(anchor1))
    localAnchorB.set(bodyB!!.getLocalPoint(anchor2))
    val d = anchor2.sub(anchor1)
    length = d.length()
  }
}
